According to color classification, OLED display devices may be grouped in monochrome type, area color type and full color type. The area color OLED display device consists of a plurality of monochrome display areas. Each display area is made from a selected monochrome luminous material. As every luminous material has different luminous efficiency, its luminosity also is different. As a result, the luminosity evenness and the color balance of the display panel are not desirable. This is the main problem now existing in the area color OLED display devices.
To resolve this problem, the most direct approach is to provide a separated and independent driving voltage or current to each luminous material. However such an approach requires to develop a driver circuit for each material. This not only increases the hardware cost, it is also not suitable for mass production. Thus its applicability is not high in the industry.